关于R语言画图标题的问题

1.转载几个总接比较好的链接： 图例篇： https://blog.csdn.net/Bone_ACE/article/details/47284805?utm_medium=distribute.pc_aggpage_search_result.none-task-blog-2_allfirst_rank_v2~rank_v25-8-47284805.nonecase&utm_term=ggplot2%E4%B8%8D%E8%A6%81%E5%9B%BE%E4%BE%8B

https://blog.csdn.net/zx403413599/article/details/48581713

https://blog.csdn.net/weixin_34199335/article/details/86113734?utm_medium=distribute.pc_aggpage_search_result.none-task-blog-2_allfirst_rank_v2~rank_v25-1-86113734.nonecase&utm_term=ggplot2%E4%B8%8D%E8%A6%81%E5%9B%BE%E4%BE%8B

坐标轴大小： http://blog.sina.com.cn/s/blog_edd63a200102xg3t.html